The present invention relates to an automatic slicing machine. More particularly this invention concerns such a machine which is equipped to wrap and seal the slices.
A standard slicing machine has an input table that can be reciprocated longitudinally past a normally circular rotating blade to cut slices from a foodstuff, for instance a piece of meat or cheese, sitting on the input table. On the other side of the blade the slices are picked up by a conveyor, typically a fork-, belt-, or chain-type arrangement having a vertical support plate and provided with a multiplicity of sharp points so that the slices can be caught on the conveyor as they issue from the downstream side of the blade. A transfer fork has tines engaged between adjacent elements of the conveyor and can be pivoted to pull the slices off the conveyor and deposit them on an output table which is positioned horizontal underneath the downstream side of the blade. Thus as the input table is moved back and forth, slices are cut from the foodstuff thereon, these slices pass the blade and are picked up the conveyor, and the transfer fork deposits them in a stack on the output table. Such machines are described in detail in my earlier U.S. Pat. Nos. 4,185,527, 4,217,650, 4,338,836, 4,379,416, 4,586,409, 4,598,618, 4,763,738, and 4,867,257.
In order to separate the slices from each other, to separate groups of slices, and/or to form a package around the slices, it is known to insert underneath the stack, between the slices, and/or on top of the stack a sheet or foil. In one system a sheet is set on the conveyor before the stack is started so that the stack is formed atop this bottom sheet, then sheets are interposed between succeeding slices as they are deposited on the bottom sheet and on each other or are interposed after a certain number of slices corresponding to a standard portion has been deposited. A top sheet is deposited on top of the stack when the desired number of slices have been deposited.
The standard system for doing this has a supply, normally a roll, of the flexible strip from which the sheets are cut and a feeder that is typically a pair of pinch rollers that can be driven to pull the flexible strip from the roll. The end of the roll is pushed by the rollers out onto a flat table and a cutter slices off the end. Then a separate manipulator normally having a plurality of suction grippers picks the sheet formed by the cut-off end and deposits it on the conveyor where the foodstuff slices are stacked.
In commonly owned U.S. Pat. No. 6,279,302 a slicing machine that deposits foodstuff slices in a stack atop a support in a stacking station has a sheet-interposing device provided with a supply roll of flexible strip and a feed roller for feeding a leading end of the flexible strip in a direction to the stacking station. A guide between the station and the roller imparts to the sheet leading end an upwardly concave U-shape to stiffen the sheet leading end so it projects horizontally stiffly from the guide above the station. A cutter movable between the guide and the station cuts off the sheet leading end so that the cut-off end drops down in the station.
Thus the equipment can comprise, normally arrayed in a row or line, an upstream paper roll and feeder, a central slicing and arraying machine, and a downstream sealing machine. In many markets this equipment is intentionally set up so the customers can watch it work, assuring themselves at the same time that they are getting what they want, and that the foodstuff is being handled by the machine in a hygienic manner. All the operator needs to do is load in the piece of meat, wurst, cheese, or the like to be sliced, set the desired slice thickness, total weight, and array type, and the machine creates a sealed package for the customer. The machine is even known to be modular, so that the supply and sealing units can be taken off the slicing/arraying unit. As a result such machines are quite large.
It is therefore an object of the present invention to provide an improved automatic slicing and packaging machine.
Another object is the provision of such an improved automatic slicing and packaging machine which overcomes the above-given disadvantages, that is which can produce a sealed package but that is of a relatively small footprint.
A slicing machine has according to the invention a main housing having a horizontal conveyor surface and a subassembly in the main housing for cutting slices from a foodstuff and depositing them on the conveyor surface. A supply housing immediately upstream of the main housing carries a supply roll of flexible strip and mechanism for feeding the flexible strip downstream toward the main housing. A cutter on the supply housing can sever a sheet from a leading end of the flexible strip. In accordance with the invention a gripper above the surface is displaceable between an upstream position generally at the cutter and a downstream position downstream of the surface. The gripper is closable to grip the leading end of the flexible strip and openable to release it. A controller connected to the gripper, to the cutter, and to the supply periodically displaces the gripper between its upstream and downstream positions so as to pull the strip downstream above the surface, operates the cutter to sever a sheet from the downstream strip end generally when the gripper reaches its downstream position, and opens the gripper in the downstream position to drop the sheet severed from the strip down onto the surface.
Thus with this system the supply housing carries the roll of flexible strip as well as the mechanism for feeding it and the cutter. These elements are mounted on a separate housing that fits right against the main housing having the cutting/arraying subassemblies so that the entire machine according to the invention is relatively compact.
In accordance with the invention the supply housing and main housing are provided with interfitting formations that hang the supply housing on the main housing. Thus the supply housing can be unhooked and taken away when the main housing and its elements need cleaning, which is particularly advantageous since the supply housing never touches the food stuff and stays quite clean.
Furthermore, a drive on the main housing includes a drive wheel exposed at an upstream end of the main housing, a drive wheel exposed at a downstream end of the supply housing, engaging the main-housing drive wheel, feed rollers on the supply housing engaging the flexible strip, and a transmission connecting the supply-housing drive wheel with the feed rollers and with the gripper for synchronous movement. Thus when the supply housing is hung on the main housing, the mechanical connection is made to the supply mechanism, eliminating the need for a separate drive for this part. The cutter on the other hand includes an electrically powered actuator and electrical contacts connected to the actuator and exposed on a downstream end of the supply housing. Control contacts on an upstream end of the main housing engage the supply-housing contacts when the supply housing is hung on the main housing to supply low voltage to the actuator, normally a solenoid, to operate it.
The gripper according to the invention has a pair of relatively movable jaws oppositely engageable with the flexible strip. A spring urges them together and cams are effective to spread them to grasp and release the leading end of the flexible strip.
According to the invention a sealer housing is provided immediately downstream of the main housing, elements in the sealer housing seal sheets of the flexible strip around slices produced by the cutter. A conveyor on the main housing forms the surface, and a drive motor in the sealer housing is connected to the conveyor in the main housing. In this system the controller is in the main housing. The connection is made by contacts like for the actuator of the cutter.
The sealer in accordance with the invention further includes a short conveyor forming an extension of the conveyor surface of the main housing, an upper heated annular die above the short conveyor, and an actuator controlled by the controller for raising the short conveyor and a slice stack thereon up into engagement with the die to fuse sheets underneath and on top of the stack together. Thus the system has on a separate housing, which also never directly contacts the foodstuff being packaged, all the parts for sealing the package made up on the middle main housing.
According to the invention a smoothing element connected to and movable upstream and downstream with the gripper is engageable downwardly with slices on the conveyor surface. A cam on the main housing raises the smoothing element as the gripper travels from the upstream to the downstream position and lowers it when moving from the downstream to the upstream position. A two-arm lever pivoted on the gripper has one arm carrying the smoothing element and another arm engageable with the cam. A spring urges the other arm into engagement with the cam.